Factors contributing to increases in serum creatinine following treatment with a sulfamethoxazole-trimethoprim combination product: Retrospective analysis of Japanese patients with normal renal function

Abstract

Japanese patients with normal renal function were retrospectively analyzed to characterize increases in serum creatinine (SCr) observed following the use of a sulfamethoxazole-trimethoprim (SMX-TMP) combination product and identify factors affecting these increases. In the patients studied (n=49), an individual comparison was conducted for the three factors of age group [≤74 years (n=21) vs. ≥75 years (n=28)], sex [male (n=24) vs. female (n=25)], and total dose throughout the treatment period [≤7 g (n=24) vs. ≥8 g (n=25)] to determine the extent of SCr increase following SMX-TMP combination product use. SCr increased significantly following SMX-TMP combination product use in patients ≤74 years of age and ≥75 years of age, in both males and females, and in patients with a total dose of ≥8 g (8 to 96 g) (p<0.05). Multivariate logistic regression analysis was used to determine the independence of these factors. Total dose was identified as an independent factor and had an odds ratio of 6.571 [95% confidence interval=1.735-24.882, p=0.006]. Post-treatment percent increases in SCr were compared using pre-treatment levels as the baseline. The group with a total dose of ≥8 g (mean 29.8 g) had a significant SCr increase of 18.4% (p=0.002), while the increase in the ≤7 g (mean 5.3 g) group was only 4.5%. The data showed that SCr increased by about 20% when the total dose taken over the treatment period was around 30 g (about 2.4 g as TMP) and indicated that total dose contributes more than age and sex to the post-treatment increase in SCr. © 2013 The Pharmaceutical Society of Japan.